Thiol-linked hyaluronic acid-mediated encapsulation of RCR-stabilized gold nanoclusters for hyaluronidase sensing and cellular imaging.

Encapsulating peptide-stabilized gold nanoclusters (AuNCs) with thiolated hyaluronic acid (HA-SH) and selectively adding cysteine to the peptide sequence increased their photoluminescence. We found that peptide compositions with cysteine in the middle emitted the most. RCR-stabilized AuNCs can be purified using size-exclusion chromatography to characterize their optical characteristics, chemical composition, and possible structure.

Ultrasound and surfactant-assisted dispersive liquid-liquid microextraction prior to poly(ethylene oxide)-mediated stacking in CE for highly sensitive determination of barbiturates in human fluids.

This study developed a facile, highly sensitive technique for extracting and quantifying barbiturates in serum samples. This method combined ultrasound and surfactant-assisted dispersive liquid-liquid microextraction with poly(ethylene oxide)-mediated stacking in capillary electrophoresis. Factors influencing the extraction and stacking performance, such as the type and volume of extraction solvents, the type and concentration of surfactant, extraction time, salt additives, sample matrix, solution pH, and composition of the background electrolyte, were carefully studied and optimized to achieve the optimal detection sensitivity.

Ultrasensitive determination of 10 phenothiazine derivatives and their enantiomers in biological fluids by capillary electrophoresis with contactless conductivity detection.

In this study, a simple, rapid, and ultrasensitive technique was developed to identify five pairs of phenothiazine drugs by using ultrasound-enhanced and surfactant-assisted dispersive liquid-liquid microextraction (UESA-DLLME), field-amplified sample injection with capillary electrophoresis (FASI-CE), and capacitively coupled capacitively coupled contactless conductivity detection (CD). During the CE separation process, UESA-DLLME was used for sample clean-up and offline concentration, and FASI-CE was used for the online concentration of phenothiazine enantiomers. At baseline, the five pairs of phenothiazine enantiomer drugs required 18 min for separation.

Ultrasensitive analysis of mirtazapine and its metabolites enantiomers in body fluids using ultrasound-enhanced and surfactant-assisted dispersive liquid-liquid microextraction followed by polymer-mediated stacking in capillary electrophoresis.

A simple, rapid, and sensitive technique for measuring mirtazapine and its metabolites enantiomers in human fluids, such as urine and serum, was developed by applying ultrasound-enhanced and surfactant-assisted dispersive liquid-liquid microextraction (USA-DLLME) integrated with poly(diallyldimethylammonium chloride) (PDDAC)-mediated stacking in capillary electrophoresis (CE). The parameters that affect extraction and stacking performance, such as the extraction volume, surfactant types, surfactant concentrations, salt additives, extraction time, solution pH, and background electrolytes, were comprehensively studied and optimized to achieve optimal detection performance. Under optimal extraction conditions (injection of 120 µL of CHCl into 1 mL of a sample solution containing 0.

Directed self-assembly of Ag-deposited MoS quantum dots for colorimetric, fluorescent and fluorescence-lifetime sensing of alkaline phosphatase.

We developed a triple-readout probe for colorimetric, fluorescent, and fluorescence-lifetime sensing of alkaline phosphatase (ALP) through the hydrolyzed ascorbic acid phosphate (AAP)-mediated formation of silver nanoparticles (AgNPs) on Ag-deposited MoS quantum dots (QDs). Ag ions were self-assembled on a monolayer MoS QD surface through the formation of Ag-S bonds. When ALP hydrolyzed AAP in an alkaline buffer, the resultant ascorbic acid (AA) triggered the reduction of the bound Ag ions into AgNPs on the MoS QD surface.

Functionalized gold nanoparticles for sensing of pesticides: A review.

Pesticides are a family of non-biodegradable chemical compounds which widely used in agriculture to control pests and increase yield production. However, overuse or abuse of pesticides and their metabolites may cause potential toxicity for the environment as well as human health and all other living organisms, even at deficient concentrations. Consequently, the development of sensors for monitoring these compounds is significant.

Ultrasound-assisted dispersive liquid-liquid microextraction coupled with field-amplified capillary electrophoresis for sensitive and quantitative determination of fluoxetine and norfluoxetine enantiomers in biological fluids.

A rapid, simple, and sensitive technique for the quantitative detection of fluoxetine and norfluoxetine enantiomers in biological fluids was developed based on the combination of field-amplified sample stacking (FASS)-related capillary electrophoresis (CE) with ultrasound-assisted dispersive liquid-liquid microextraction (UA-DLLME). The extraction efficiency of UA-DLLME was strongly related to extraction time, salt concentration, type of extraction and dispersion solvents, and volume of extraction and dispersion solvents. The extracted fluoxetine and norfluoxetine enantiomers in a mixture of 50% methanol and 50% deionized water were efficiently stacked using FASS and then separated using cyclodextrin-modified CE.

Inhibition of catalytic activity of fibrinogen-stabilized gold nanoparticles via thrombin-induced inclusion of nanoparticle into fibrin: Application for thrombin sensing with more than 10-fold selectivity.

Citrate-capped gold nanoparticles (AuNPs) modified with thrombin-binding aptamer are often implemented for colorimetric, fluorescent, and electrochemical detection of thrombin in an aqueous solution. However, researchers have rarely explored the application of fibrinogen-modified AuNPs (F-AuNPs) for thrombin sensing. We present a simple, inexpensive, sensitive, and selective probe for colorimetric assay of thrombin through combining thrombin-induced inclusion of F-AuNPs into Fibrin and F-AuNPs-catalyzed reduction of 4-nitrophenol with an excess amount of NaBH.

Enantioseparation of phenothiazines through capillary electrophoresis with solid phase extraction and polymer based stacking.

This study developed a sensitive method involving capillary electrophoresis (CE) coupled with ultraviolet absorption for the simultaneous separation of chiral phenothiazine drugs at nanomolar concentration levels. The method consists of hydroxypropyl-γ-cyclodextrin (Hp-γ-CD) as a chiral selector and poly (diallyldimethylammonium chloride) (PDDAC)-based CE. Five pairs of d,l-phenothiazines were baseline separated using a background electrolyte containing 0.

Dispersive liquid-liquid microextraction combined with acetonitrile stacking through capillary electrophoresis for the determination of three selective serotonin reuptake inhibitor drugs in body fluids.

Dispersive liquid-liquid microextraction was combined with acetonitrile stacking in capillary electrophoresis for the identification of three selective serotonin reuptake inhibitors (citalopram, fluoxetine, and fluvoxamine) in human fluids such as urine and plasma. Parameters that affect the extraction and stacking efficiency, such as the type and volume of the extraction and disperser solvent, extraction time, salt addition for dispersive liquid-liquid microextraction, and sample matrices, pH, and concentration of the separation buffer for stacking, were investigated and optimized. Under optimum conditions, the enrichment factors were in the range of 1195-1441.

Recent Advances in the Determination of Pesticides in Environmental Samples by Capillary Electrophoresis.

Nowadays, owing to the increasing population and the attempts to satisfy its needs, pesticides are widely applied to control the quantity and quality of agricultural products. However, the presence of pesticide residues and their metabolites in environmental samples is hazardous to the health of humans and all other living organisms. Thus, monitoring these compounds is extremely important to ensure that only permitted levels of pesticide are consumed.

Sensitive detection of piperazinyl phenothiazine drugs by field-amplified sample stacking in capillary electrophoresis with dispersive liquid-liquid microextraction.

A rapid, simple and sensitive method for the detection of piperazinyl phenothiazine drugs using dispersive liquid-liquid microextraction (DLLME) combined with field-amplified sample stacking (FASS) in CE was developed. Sensitivity parameters that affect the extraction and FASS efficiency, such as the type and volume of disperser solvent, extraction time, addition of salt, and efficiency of FASS, were investigated and optimized. Note that the conductivity ratio between BGE and sample zone was measured to be 2300.

Combination of poly(diallyldimethylammonium chloride) and hydroxypropyl-γ-cyclodextrin for high-speed enantioseparation of phenothiazines by capillary electrophoresis.

High-speed capillary electrophoresis (CE) enables the simple, rapid, and inexpensive analysis of large sets of chiral samples in the pharmaceutical industry. Hence, we developed a novel method for separating enantiomers of d,L-phenothiazines simply and rapidly, based on using poly(diallyldimethylammonium chloride) (PDDAC) as an additive and hydroxypropyl-γ-cyclodextrin (Hp-γ-CD) as a chiral selector in capillary electrophoresis. Adding 0.

On-line sample preconcentration by sweeping and poly(ethylene oxide)-mediated stacking for simultaneous analysis of nine pairs of amino acid enantiomers in capillary electrophoresis.

This study proposes a sensitive method for the simultaneous separation and concentration of 9 pairs of amino acid enantiomers by combining poly(ethylene oxide) (PEO)-based stacking, β-cyclodextrin (β-CD)-mediated micellar electrokinetic chromatography (MEKC), and 9-fluoroenylmethyl chloroformate (FMOC) derivatization. The 9 pairs of FMOC-derivatized amino acid enantiomers were baseline separated using a discontinuous system, and the buffer vials contained a solution of 150 mM Tris-borate (TB), 12.5% (v/v) isopropanol (IPA), 0.

Separation of amino acids by capillary electrophoresis with light-emitting diode-induced fluorescence in the presence of electroosmotic flow.

In this chapter, we describe a method to identify amino acids (AA) by capillary electrophoresis in conjunction with light-emitting diode-induced fluorescence (LEDIF). First, amino acids labeled with naphthalene-2,3-dicarboxaldehyde (NDA) in the presence of cyanide are converted to highly fluorescent cyanobenz[f]isoindole (CBI) derivatives. Next, they are separated by gel electrophoresis in the presence of EOF.

Sensitive determination of sertraline by capillary electrophoresis with dispersive liquid-liquid microextraction and field-amplified sample stacking.

A novel method for the determination of sertraline using dispersive liquid-liquid microextraction (DLLME) coupled with capillary electrophoresis (CE) was developed. Acetone and dichloromethane were used as the disperser solvent and extraction solvent, respectively. A mixture of the extraction and disperser solvents was rapidly injected into a 1.

On-line concentration and separation of cationic and anionic neurochemicals by capillary electrophoresis with UV absorption detection.

This paper presents on-line simultaneous concentration and separation of cationic and anionic neurochemicals by capillary electrophoresis (CE) with UV absorbance spectroscopy. Neurochemical stacking exploits differences in local electric field and viscosity between the sample zone and the background electrolyte (BGE). To achieve these discontinuous conditions for CE, neurochemicals were prepared in a solution containing 1mM formic acid and 20% (v/v) acetonitrile (ACN).

Selective extraction of thiol-containing peptides in seawater using Tween 20-capped gold nanoparticles followed by capillary electrophoresis with laser-induced fluorescence.

This study combines Tween 20-capped gold nanoparticles (Tween 20-AuNPs) with capillary electrophoresis (CE) for ultrasensitive detection of thiol-containing peptides, including glutathione (GSH), γ-glutamylcysteine (γ-GCS), and phytochelatin analogs. By forming AuS bonds, Tween 20-AuNPs can selectively extract and enrich these thiols from a complicated matrix. A Tween 20 capping layer not only suppresses nonspecific adsorption, but also enables NPs to disperse in a highly salinity solution.

Stacking and separation of aspartic acid enantiomers under discontinuous system by capillary electrophoresis with light-emitting diode-induced fluorescence detection.

We describe the stacking and separation of d- and l-aspartic acid (Asp) by capillary electrophoresis (CE) with light-emitting diode-induced fluorescence detection (LEDIF). In the presence of cyanide, d- and l-Asp were derivatized with naphthalene-2,3-dicarboxaldehyde (NDA) to form fluorescent derivatives prior to CE-LEDIF. The separation of NDA-derivatized d- and l-Asp was accomplished using a discontinuous system - buffer vials contained a solution of 0.

Highly sensitive detection of chiral amino acids by CE based on on-line stacking techniques.

We report a novel means for chiral separation and stacking of amino acids by MEKC with LED-induced fluorescence detection. Naphthalene-2,3-dicarboxaldehyde, hydroxypropyl-beta-cyclodextrin (Hp-beta-CD), SDS, and poly(ethylene oxide) (PEO) serve as a derivatized agent, chiral selector, pseudostationary phase, and concentrated medium, in sequence. To improve speed, resolution, and stacking efficiency, the analysis of chiral amino acids was performed under discontinuous conditions--the capillary was filled with a solution of 100 mM Tris-borate, 150 mM SDS, and 50 mM Hp-beta-CD, whereas buffer vials contain 20 mM Tris-borate, 150 mM SDS, 50 mM Hp-beta-CD, and 0.

Selective enrichment of aminothiols using polysorbate 20-capped gold nanoparticles followed by capillary electrophoresis with laser-induced fluorescence.

In this article, we report a simple method for selective enrichment of aminothiols using Tween 20-capped gold nanoparticles (AuNPs) prior to capillary electrophoresis coupled with laser-induced fluorescence (CE-LIF). Compared to citrate-capped AuNPs, Tween 20-capped AuNPs exhibit the ability to disperse in a highly saline solution and selectively extract aminothiols through the formation of Au-S bonds. After extraction and centrifugation, 1mM thioglycollic acid (TGA) was utilized to remove aminothiols that attached to the NP surfaces.

On-line concentration and separation of indolamines, catecholamines, and metanephrines in capillary electrophoresis using high concentration of poly(diallyldimethylammonium chloride).

This paper tackles a simple and efficient method for the simultaneous separation and stacking of neurotransmitters in capillary electrophoresis with UV detection. By using poly(diallyldimethylammonium chloride) (PDDAC) as a buffer additive, the high and reversed EOF are observed. Moreover, the mobility of indolamines and catecholamines decreases as the PDDAC concentration increases.

Determination of amino acids in tea leaves and beverages using capillary electrophoresis with light-emitting diode-induced fluorescence detection.

The combination of capillary electrophoresis (CE) and light-emitting diode-induced fluorescence (LED-IF) detection has been demonstrated in the analysis of major amino acids in tea leaves and beverages. The separation efficiency of amino acids, which were derivatized with naphthalene-2,3-dicarboxaldehyde (NDA), depended on the capillary length and PEO concentration. We suggested that the interactions between the NDA derivatives and poly(ethylene oxide) (PEO) molecules are based on hydrogen bonding, hydrophobic patches, and Van der Waals forces.

On-line concentration of microheterogeneous proteins by capillary electrophoresis using SDS and PEO as additives.

In this paper, we describe a method for analyzing large-volume protein samples using capillary electrophoresis in conjunction with laser-induced fluorescence detection (CE-LIF). To improve the stacking and separation efficiencies of proteins, we added either 0.01% sodium dodecyl sulfate (SDS) or 0.